1. Field of the Invention
The present invention relates to systems and apparatus for dissipating heat. More specifically, the present invention relates Stifling cycle type cooling systems and similar apparatus.
2. Description of the Related Art
In many applications, dissipation of heat is a significant concern for systems designers. Cooling systems such as Stirling Cycle coolers, have been developed and used successfully to maintain operating temperatures of circuits, devices and components within specified ranges. Unfortunately, the cooler itself represents a point source of heat. On a spacecraft, this point source may be embedded deep within the spacecraft. Hence, heat dissipation is particularly problematic in spacecraft applications as ambient air is typically not available as a heat sink. As a result, the thermal energy must be moved to a radiating panel on the spacecraft. There are at least two conventional approaches to this problem.
First, a conductor may be used to transport thermal energy. However, this approach may require 30-50 additional pounds of dead weight in conductive material such as copper. Notwithstanding the cost of the conductor and the labor associated with its installation, the launch cost alone (approximately $50,000 per pound) is such that this option is not attractive for most applications.
A second conventional approach involves the use of heat pipes. A heat pipe is a self-contained, typically rigid structure in which a working fluid is heated to a vapor by an external heat source. The vapor carries the thermal energy to a distal cold end of the pipe where it condenses back into liquid form. The liquid returns to the warm end and the process repeats until the warm end and the cold end are at a point of equilibrium. Unfortunately, the rigid heat pipes are difficult to integrate into a spacecraft structure and still impose some weight penalty.
Hence, a need remains in the art for a lightweight, low cost system or technique for dissipating heat in spacecraft and other applications.